For the Sausages: Heat the oil in dish. After the oil has been heated, add the sausages to the dish and put in the oven that is heated to 160*C. Cook the sausages for 40 mins. After 20 mins, turn over sausages.
For the Potatoes: Start to peel the potatoes until no skin remains. Chop the potatoes into chunks. Boil the potatoes in half a pan of water for 20 - 25 mins. Drain potatoes using the colander. Put the potatoes back in the pan and mash. Add in the butter and milk. Season with salt and pepper. Put a drop of food colouring in to make it a scary colour!
For the Gravy: Peel and chop the onions. Fry onions until soft. Whilst onions are frying, mix gravy granules with boiling water. Then add gravy to the onions.
For Presentation of dish: Add the sausages onto a plate. Next to the sausages, add a big spoonful of mash. With the ladel, pick up the gravy and pour over the sausgaes and mash.
And then... TA-DA! You have made a brilliant Sausage and Mash with Onion Gravy!